Even Short-Lived Greenhouse Gases Create Centuries of Problems to the Earth's Oceans

The greenhouse gases that humans are emitting now may not stay in the atmosphere forever, but their destructive effects will outlive us all.

According to a report from Washington Post, there's a new study published in the journal of Proceedings of the National Academy of Sciences that highlights the time that greenhouse gases affects the planet. Even materials that break down quickly in the atmosphere - such as methane - can have effects on the sea for hundreds of years in the future.

Thermal expansion is when the greenhouse gases rise to the atmosphere leading to a significant increase in temperature. The heat gets absorbed by the ocean causing water expansion. Scientists factor in this process when predicting sea level rise in the future. In fact, even if the people stops emitting greenhouse gases, the sea would keep expanding for centuries.

"The ocean never forgets - that's the essential message of this paper," Susan Solomon, a professor of environmental studies at the Massachusetts Institute of Technology (MIT), said.

Solomon and the rest of the team used a climate model that let them observe different greenhouse gases and their effects on the ocean. They assumed high emissions in the future, observing various gases including carbon dioxide, methane, nitrous oxide and various halocarbons. The scientists simulated the scenarios with continuous emissions until 2050 when they halted all to decrease their atmospheric levels.

The report revealed that other gases last in the atmosphere for a relatively short time, especially compared to carbon dioxide, which can stay in the air for 200 years or more. Methane, for one, is only up there for around a decade. Still, the effects -- particularly thermal expansion - of these seemingly short-lived greenhouse gases linger in the ocean for centuries. This new model shows that up to 75 percent of the maximum amount of thermal expansion caused by methane could endure after a hundred of years, and 40 percent after 500 years.

Researchers reveal that the reason for the extended period of time stems from the ocean currents moving throughout the world, spreading the heat.

"If you think of countries like Tuvalu, which are barely above sea level, the question that is looming is how much we can emit before they are doomed," Solomon pointed out in a report from The Science Explorer. "Are they already slated to go under, even if we stopped emitting everything tomorrow? It's all the more reason why it's important to understand how long climate changes will last, and how much more sea-level rise is already locked in."